Insert for rail car coupling

ABSTRACT

A shell-like insert made from a low-friction material is useful in a coupler for railway cars. The coupler may have a male connector on one car and a female connector on the other. The connectors conform to each other and provide a clearance space therebetween. The male connector may include a ball stud and the female connector may provide a socket for the ball. The insert conforms to the clearance space and is made from a low-friction material, such as PTFE, a filament wound composite or an epoxy-impregnated PTFE and glass-fiber material, or the like. A railway car assembly may include two cars joined by a coupler as described herein. The cars may be joined by providing a rear follower and a front follower in the female connector to provide the socket, and positioning an insert in the socket between the ball and one or both followers.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. provisional application No. 60/965,683 filed Aug. 20, 2007, the contents of which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention is generally directed to a railway car coupler and is more specifically directed to an insert for a railway car coupling apparatus.

BACKGROUND

Some railway car couplers comprise a male connector on one car and a female connector on another car. In a particular type of coupler, the male connector comprises a ball stud. The ball on the ball stud is secured within a female coupler housing by two followers, one on the distal end of the ball stud (the rear follower) and one at the neck of the ball stud (the front follower). The followers define a socket within which the ball is secured to provide an articulated joint that couples the cars together. The followers may be equipped with metal inserts that reside in a clearance space between the ball and the followers. When fluid lubricant (such as grease) is injected into the joint, the inserts serve to reduce wear of the ball and the followers. However, such lubrication efforts add to the maintenance burden of maintaining the coupler and, if overlooked, lead to severe wear in the coupler.

Based on the foregoing, it is the general object of this invention to provide an improvement over prior art rail car couplers.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a shell-like insert comprising a low-friction polymeric material.

In another aspect, this invention provides an insert for a coupler that comprises a male connector and a female connector. The female connector has surfaces that are configured to conform to the male connector and to provide a clearance space therebetween. The insert is configured to conform to the clearance space and comprises a low-friction polymeric material.

In still another aspect, this invention provides a coupler that comprises a male connector and a female connector that has surfaces configured to conform to the male connector and to provide a clearance space therebetween. There is an insert situated in the clearance space, the insert being made from a low-friction polymeric material.

According to another embodiment, the invention provides a railway car assembly comprising a first railway car having a male connector and a second railway car having a female connector, the male connector and the female connector together comprising a coupler as described herein.

The invention provides a method aspect by which a first railway car may be coupled to a second railway car. The first railway car comprises a male connector that comprises a ball stud and the second railway car comprises a female connector thereon. The method includes providing a rear follower and a front follower in the female connector, securing the ball of the ball stud in a socket defined by the rear follower and the front follower, and positioning an insert in the socket. The insert is situated between the ball and the rear follower and between the ball and the front follower and is made from a low-friction polymeric material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic partly cross-sectional view of a coupler comprising an insert in accordance with a specific embodiment of the invention;

FIG. 2 is a schematic perspective view of a follower for a coupler for use with the present invention;

FIG. 3 is a partly cross-sectional elevation view of an insert configured for positioning between the follower of FIG. 2 and the ball of the coupler of FIG. 1, according to one specific aspect of the invention;

FIG. 4 is a schematic perspective view of a follower for a coupler for use with the present invention; and

FIG. 5 is an elevation view of an insert configured for positioning between the follower of FIG. 4 and the ball of the coupler of FIG. 1, according to one specific aspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION

This invention provides an improvement to a male-female railway car coupler by providing an insert that resides in the clearance space between the male coupler and the female coupler. The insert is made from a polymeric material that has a low coefficient of friction and therefore provides a lubrication effect that protects the followers from wear and that facilitates movement of the male coupler in the female coupler. The insert is fabricated from hard, smooth, wear-resistant composite material (referred to herein as a “low friction” material) such as a filament wound composite or an epoxy-impregnated polytetrafluoroethylene (PTFE) and glass-fiber material. The insert lasts longer than a prior art injection of grease into a prior art coupling and is easily removable from the coupler, and is easily replaceable. Therefore, the insert reduces or eliminates the need to inject fluid lubricant into the coupler joint, and thus reduces the maintenance task requirements for the railway cars.

The insert is configured to conform to the clearance space between the male coupler and the female coupler. Thus, the insert may be configured to have a shell-like configuration, with the concave interior surface sized to engage the surface of the ball of a ball stud and a convex exterior surface sized to engage the concave surface of a follower. Accordingly, the insert will have a predetermined thickness and inner and outer diameters that conform to the coupler. Optionally, the insert will be configured to meet the size and shape criteria of a prior art insert for the coupler. The insert may be configured to engage only a portion of the socket. For example, an insert may be configured to engage only the concave portion of one follower in a ball-and-socket coupler that comprises two or more followers.

FIG. 1 illustrates one specific coupler with which the present invention may be used. The coupler 10 comprises a male connector 12 and a female connector 14. The male connector 12 has a ball head 12 a and a neck 12 b. The female connector 14 includes a housing 15 within which a rear follower 16 and a front follower 18 are received. The rear follower 16 and the front follower 18 are configured to reside within the housing of the female connector 14 and to define a socket that retains the ball head 12 a therein, within which socket the ball head 12 a can pivot. The coupler 10 is configured so that the male connector 12 and the female connector 14 form an articulated joint. In this embodiment, the rear follower 16 and the front follower 18 each comprise a concave surface that conforms substantially to the convex, substantially spherical surface of the ball head 12 a. However, the radius of curvature to which the rear follower 16 and the front follower 18 conform is sufficiently larger than the diameter of the ball head 12 a to provide a clearance space between them for an insert.

The rear follower 16 may have a fully round concave surface 16 a formed therein, as indicted in FIG. 2. Accordingly, the rear follower 16 may be positioned in the housing of the female connector 14 before the ball head 12 a of the male connector 12 is inserted therein. An insert 20, shown in FIG. 3, is dimensioned and configured to substantially conform to the clearance provided between the ball head 12 a and the rear follower 16. In use, the insert 20 is positioned between the ball head 12 a and the concave surface on the rear follower 16 before the male connector 12 is secured in the female connector 14. Optionally, the insert 20 may be mounted either in the rear follower 16 or on the ball head 12 a before the male connector 12 is secured in the female connector 14, or the insert 20 may simply be positioned between the ball head 12 a and the rear follower 16 as the coupler is being assembled.

After the ball head 12 a is inserted into the female connector 14, the front follower 18 can be fitted over the neck 12 b. The front follower 18 is configured as a yoke that can fit over the neck 12 b of the male connector 12, as indicated in FIG. 4. Accordingly, the concave surface 18 a on the front follower 18 is slotted and, therefore, is not fully round. A second insert 22, depicted in FIG. 5, may be configured to be disposed in the clearance space between the front follower 18 and the ball head 12 a.

After the rear follower 16 and insert 20 are positioned in the housing 15 and the ball head 12 a is advanced into the female connector 14, the insert 22 and the front follower 18 are positioned in the female connector 14 to form the socket that secures the ball head 12 a in the housing 15.

One or both of inserts 20 and 22 are made from a low-friction material as described herein.

In various embodiments, the insert may comprise a laminate that comprises two outer layers that define the surfaces of the laminate (the “surface layers”) and, optionally, one or more additional intermediate layers between the outer layers.

A first outer layer that defines the concave surface (that that bears directly on the male coupler) optionally comprises PTFE. The PTFE layer may be about 0.01 to about 0.04 inch (in.) (about 0.25 to about 1 millimeter (mm)) thick, optionally about 0.012 to about 0.015 in. (about 0.3 to about 0.4 mm) thick. A second outer layer may comprise a fiber-reinforced epoxy compound or a rubber-containing paint.

In one three-layer embodiment, there is an intermediate layer adjacent to the first outer layer, and the second outer layer is adjacent to the intermediate layer. The intermediate layer comprises a matrix of bisphenol epoxy resin into which one or more particulates and/or fibers are mixed. For example, the intermediate layer may comprise fumed silica and/or fiberglass fibers in an epoxy resin. Optionally, the intermediate layer may contain PTFE. For example, powdered PTFE may be mixed into the epoxy resin. The second outer layer may comprise a high-performance, carbon fiber-reinforced epoxy molding compound.

In an alternative three-layer embodiment, the second outer layer may comprise a rubber-containing paint.

To produce the insert, the mixture of the intermediate layer is applied, in uncured form, onto the first outer layer, and the second outer layer may be applied in uncured form, onto the intermediate layer. The three layers are then pressed in a mold designed to conform the insert to the clearance space in the coupler. The laminate is then cured and may then be machined for better conformance to the coupler.

In one specific three-layer embodiment, the first outer layer comprise PTFE and the intermediate layer comprises a Bisphenol-A epichlorohydrin based epoxy resin (e.g., phenol, 4,4O-(1-methylethylidene) bis-polymer with (chloromethyl) oxirane) such as EPON™ 828 sold by Hexion Specialty Chemicals, Inc., filled with hydrophilic fumed silica having a surface area of 200 square meters per gram (m²/g). Unfilled, the epoxy resin of the intermediate layer may have tensile values greater than 10,000 psi (69 MPa) with modulus values greater than 400,000 psi (2750 MPa).

The second outer layer comprises a high-performance, carbon fiber-reinforced epoxy molding compound such as LYTEX™ 4149 sold by Quantum Composites, Inc. Such a molding compound may have one or more of the characteristics set forth in the following table, when cured:

TABLE Test Procedure Value Specific Gravity ASTM D-792 1.45 Shrinkage, inch/inch (mm/mm) ASTM D-955 0.000 (0.000) Flexural Strength, psi (MPa)¹ ASTM D-790 89,000 (613) Flexural Modulus, psi (GPa)¹ ASTM D-790 5.0 × 10⁶ (34.5) Tensile Strength, psi (MPa)¹ ASTM D-638 42,000 (289) Tensile Modulus, psi (GPa)¹ ASTM D-638 8.0 × 10⁶ (55.1) Ultimate Elongation, % ASTM D-638 0.487 Izod Impact, notched, ft.lb/in. (J/m) ASTM D-256 18 (960) Compression Strength, psi (MPa)¹ ASTM D-695 40,000 (275 Compression Modulus, psi (GPa)¹ ASTM D-695 4.6 × 10⁶ (31.7) Shear Strength, in-plane, psi (MPa)¹ ASTM D-5379 30,000 (206) Shear Modulus, in-plane, psi (GPa)¹ ASTM D-5379 1.6 × 10⁶ (11) Shear Strength, interlaminar, psi (MPa)¹ ASTM D-5379 9,500 (65.5) Shear Modulus, interlaminar, psi (GPa)¹ ASTM D-5379 0.42 × 10⁶ (2.9) Coefficient of Thermal Expansion TMA 2 × 10⁻⁶/° F. Heat Deflection Temperature @ 264 psi stress, ° F. ASTM D-648 >575° F. (300° C.) (° C.) Continuous Use Temperature (1000 hrs.) 350° F. (175° C.) Thermal Conductivity, Watts/M ° K 0.474

In an alternative specific embodiment, the bisphenol epoxy of the intermediate layer is filled with fiberglass fibers instead of fumed silica.

In still another alternative embodiment, an outer layer may comprise an epoxy resin having PTFE mixed therein.

The term “resin” is meant to include uncured resins and/or the cured products of those resins, unless the term is modified by “cured” or “uncured”. The terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. In addition, the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

Although the invention has been described with reference to particular embodiments thereof, it will be understood by one of ordinary skill in the art, upon a reading and understanding of the foregoing disclosure, that numerous variations and alterations to the disclosed embodiments will fall within the spirit and scope of this invention and of the appended claims. 

1. A shell-like insert comprising a low-friction polymeric material.
 2. The insert of claim 1, wherein the insert is a laminate comprising at least a first outer layer and a second outer layer.
 3. The insert of claim 1, wherein the insert is a laminate comprising a first outer layer, an intermediate layer and a second outer layer.
 4. The insert of claim 3, wherein the first outer layer comprises PTFE, the intermediate layer comprises a filled epoxy resin and the second outer layer comprises a carbon fiber-reinforced epoxy layer.
 5. The insert of claim 3, wherein the first outer layer comprises PTFE, the intermediate layer comprises a filled epoxy resin and the second outer layer comprises a rubber-containing paint.
 6. The insert of claim 1 having outer surfaces configured to conform to a male connector and to a female connector of a coupler, the male connector and the female surfaces being configured to provide a clearance space therebetween; the insert being configured to conform to the clearance space.
 7. A coupler comprising: a male connector; a female connector having surfaces configured to conform to the male connector, the surfaces being configured to provide a clearance space therebetween; and an insert situated in the clearance space; wherein the insert comprises a low-friction polymeric material.
 8. The insert of claim 7, wherein the insert is a laminate comprising at least a first outer layer and a second outer layer.
 9. The insert of claim 7, wherein the insert is a laminate comprising a first outer layer, an intermediate layer and a second outer layer.
 10. The insert of claim 9, wherein the first outer layer comprises PTFE, the intermediate layer comprises a filled epoxy resin and the second outer layer comprises a carbon fiber-reinforced epoxy layer.
 11. The insert of claim 9, wherein the first outer layer comprises PTFE, the intermediate layer comprises a filled epoxy resin and the second outer layer comprises a rubber-containing paint.
 12. The insert of claim 7, having outer surfaces configured to conform to a male connector and to a female connector of a coupler, the male connector and the female surfaces being configured to provide a clearance space therebetween; the insert being configured to conform to the clearance space.
 13. A railway car assembly comprising: a first railway car having a male connector; a second railway car having a female connector engaged with the male connector, the male connector and the female surfaces being configured to provide a clearance space therebetween; the insert being configured to conform to the clearance space; and an insert in the clearance space, the insert comprising a low-friction polymeric material.
 14. The insert of claim 13, wherein the insert is a laminate comprising at least a first outer layer and a second outer layer.
 15. The insert of claim 13, wherein the insert is a laminate comprising a first outer layer, an intermediate layer and a second outer layer.
 16. The insert of claim 15, wherein the first outer layer comprises PTFE, the intermediate layer comprises a filled epoxy resin and the second outer layer comprises a carbon fiber-reinforced epoxy layer.
 17. The insert of claim 15, wherein the first outer layer comprises PTFE, the intermediate layer comprises a filled epoxy resin and the second outer layer comprises a rubber-containing paint.
 18. The insert of claim 13 having outer surfaces configured to conform to a male connector and to a female connector of a coupler, the male connector and the female surfaces being configured to provide a clearance space therebetween; the insert being configured to conform to the clearance space.
 19. A method for coupling a first railway car to a second railway car, wherein the first railway car comprises a male connector that comprises a ball stud and the second railway car comprises a female connector thereon, the method comprising: providing a rear follower and a front follower in the female connector; securing the ball of the ball stud in a socket defined by the rear follower and the front follower; and positioning an insert in the socket between the ball and the rear follower and between the ball and the front follower; wherein the insert is made from a low-friction polymeric material.
 20. The insert of claim 19, wherein the insert is a laminate comprising at least a first outer layer and a second outer layer.
 21. The insert of claim 19, wherein the insert is a laminate comprising a first outer layer, an intermediate layer and a second outer layer.
 22. The insert of claim 21, wherein the first outer layer comprises PTFE, the intermediate layer comprises a filled epoxy resin and the second outer layer comprises a carbon fiber-reinforced epoxy layer.
 23. The insert of claim 21, wherein the first outer layer comprises PTFE, the intermediate layer comprises a filled epoxy resin and the second outer layer comprises a rubber-containing paint.
 24. The insert of claim 19 having outer surfaces configured to conform to a male connector and to a female connector of a coupler, the male connector and the female surfaces being configured to provide a clearance space therebetween; the insert being configured to conform to the clearance space. 